The advantages of guardrail cleaning vehicle diesel engine are high power and good economic performance. The working process of a diesel engine is much the same as that of a gasoline engine. However, diesel engines use diesel fuel, which has a higher viscosity than gasoline and is not easy to evaporate, while its spontaneous combustion temperature is lower than gasoline. Therefore, the formation and ignition of combustible mixture is different from gasoline engines. The main difference is that the mixture in a diesel engine cylinder is compressed, not ignited. Diesel engine air into the cylinder is at work, at the end of the compressed air in cylinder, the temperature can reach 500-500 ℃, pressure can be up to 40-50 atmospheric pressure. Check point near the end of the piston, the engine of the high pressure pump with high pressure in the cylinder injection diesel, diesel form of subtle oil grains, mixed with high pressure high temperature air, diesel mixture combustion, violent expansion, produce explosive force, driving the piston downward to do work, the temperature can reach 1900-2000 ℃, pressure can reach 60-100 atmospheric pressure, the power is very big, so the diesel engines are widely used in large diesel cars.
Characteristics of traditional diesel engines: thermal efficiency and economic efficiency are better. Diesel engines use compressed air to raise air temperature so that air temperature exceeds diesel's spontaneous combustion point. At this time, diesel fuel, diesel spray and air are injected into the engine to ignite on its own at the same time. Therefore, diesel engines do not require a ignition system. At the same time, the fuel supply system of diesel engine is relatively simple, so the reliability of diesel engine is better than that of gasoline engine. Due to the freedom from deflagration and the need of diesel spontaneous combustion, diesel engine compression ratio is very high. Both thermal efficiency and economic efficiency are better than gasoline engines. At the same time, under the same power, diesel engine has high torque and low speed at the maximum power, which is suitable for the use of freight cars.
However, due to the high working pressure of diesel engine, the relevant parts are required to have high structural strength and stiffness, so the diesel engine is relatively heavy and large. Diesel oil pump and nozzle manufacturing precision requirements are high, so the cost is high; In addition, diesel engine works rough and has high vibration and noise. Diesel is not easy to evaporate, cold winter when starting the car is difficult. Due to the above characteristics, diesel engines used to be used in large and medium truck. New development for small, high-speed diesel engines: emissions have reached European III standards. Traditionally, diesel engines have been rarely favored by cars due to their heavy weight, low power, high noise and vibration, and heavy carbon smoke and particle (PM) emissions. But with the progress of diesel engine technology in recent years, especially the new development of the small high-speed diesel engine, a batch of advanced technologies, such as electronic direct injection, common rail, turbocharged and inter-cooled technology can be used in small diesel engine, make originally the disadvantages of the diesel engine has been better solved, and the advantage in energy saving and CO2 emissions of diesel engine, are all heat engines, including gasoline engine, can't replace, therefore, the advanced small high-speed diesel engine, the number has reached the European III emission standard, at present has become the European and American many new cars power plant, predictably, More and more diesel cars will appear in our country.
A gasoline engine usually sprays gasoline into the intake pipe and air to mix into a combustible mixture and then enters the cylinder through spark plug ignition expansion work. People usually call it a ignition engine. Generally, diesel engines inject diesel directly into the engine cylinder through injection pump and nozzle, and uniformly mix the compressed air in the cylinder, and spontaneously ignite at high temperature and high pressure to drive the piston to perform work. This engine is commonly referred to as a compression engine.
Generally, diesel engine is 30% higher than gasoline engine in thermal efficiency. Therefore, from the perspective of energy saving and fuel cost reduction, the popularization of diesel engine car is of great significance. Compared with gasoline engines, diesel engines are characterized by high power, long service life and good power performance. The greenhouse effect generated by diesel engines is 45% lower than that of gasoline, and the carbon monoxide and hydrocarbon emissions are also low. The nitrogen and oxygen emissions of the whole vehicle are slightly higher than that of gasoline engines. The disadvantage of diesel engines is the high emission of harmful particulate matter. In recent years, diesel engines have adopted advanced technologies such as turbocharging, medium-cooling, direct injection, catalytic conversion of tail gas and particle collector, and emissions of diesel engines have reached euro III and euro IV emission standards.
The ability of a vehicle to accomplish unit transportation with minimal fuel consumption under certain operating conditions is known as the fuel economy of a vehicle. Fuel economy is one of the main performance of automobile. Fuel usually accounts for about 37% of the cost of running a car. The main factors that affect the fuel economy of automobile are as follows: first of all, the engine's thermal efficiency, intake efficiency and friction loss should be improved. Second, reduce the body weight, reduce air resistance, reduce the rolling resistance of the wheels. Third, improve transmission efficiency and match the speed ratio reasonably. In terms of usage, different grades of road use different fuel. Traffic congestion and heavy congestion are totally different from the fuel consumption of smooth traffic. Wind, rain, and climate change all affect fuel consumption. Driver technology is also important to fuel consumption levels. There are many factors that affect the fuel economy of automobile, among which the most important is the automobile engine itself.